JP2603367B2 - Coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition used for hard coating, rust-proof coating, thick-film coating, vibration-damping coating, heat-insulating coating, conductive coating, etc., and particularly relates to an organic component and an inorganic component. And a coating composition that forms a composite cured film by bonding to the composition.

[0002]

2. Description of the Related Art In general, inorganic coatings (coatings) such as silicate coatings or polysiloxane coatings have high surface hardness, abrasion resistance, scratch resistance, heat resistance, and chemical resistance. Stable. However, the coating is brittle and has relatively low adhesion to the substrate. On the other hand, a coating made of an organic material such as various resins is rich in flexibility and excellent in adhesion to a substrate and the like. Therefore, in order to make use of the advantages of both, conventionally, an inorganic / organic composite coating in which an inorganic substance and an organic substance are combined has been developed. However, in practice, there are not many examples in which an inorganic substance and an organic substance directly react to form a stable composite film.

[0003] That is, as an example of a composition for forming an inorganic-organic composite type coating film known so far, for example,
In Japanese Patent Publication No. 53-6033, a combination of an inorganic component composed of ethyl silicate and an organic component composed of polyvinyl butyral is used. In Japanese Patent Publication No. 55-41711-41713, an inorganic component such as colloidal silica, a silane coupling agent and an organic component are used. There is a bond with a certain acrylic copolymer, modified alkyd resin, modified epoxy resin,
In addition, JP-B-54-20210 and JP-B-55-20210
Japanese Patent No. 41274 discloses a technique in which similar components are combined. And, in these composite coatings, the compatibility between the wear resistance or the scratch resistance and the flexibility is mainly achieved.

[0004]

As described above, some examples of inorganic / organic composite coatings in which an inorganic substance and an organic substance are combined have been known. However, even in the case of using colloidal silica, these coatings are rather composed mainly of an organic resin component, and the inorganic component is rather a modifier component thereof. Therefore, their properties do not depart from the properties of the organic resin film, and although the heat resistance and the abrasion resistance are improved, the properties of the inorganic film are not sufficiently exhibited and the surface hardness and the like are still insufficient. There was an inadequate tendency.

The present inventors have repeated various trials and errors and studies on a coating composition capable of forming an inorganic / organic composite type film. As a result, the polyisocyanate and a certain kind of inorganic fine particles are directly reacted. To form a coating having the properties of an inorganic substance and the properties of an organic substance, that is, high in hardness and rich in flexibility (flexibility, toughness),
It has also been found that a film having excellent abrasion resistance (scratch resistance), heat resistance, adhesion, stain resistance, chemical stability and the like is formed.

Accordingly, an object of the present invention is to provide a coating composition capable of forming a coating film having a combination of excellent properties of an inorganic substance and an organic substance such as high hardness and flexibility. .

[0007]

According to a first aspect of the present invention, there is provided a coating composition comprising a colloidal silica having a silanol group on its surface and a silanol group on the surface of the colloidal silica which reacts and bonds with each other to form a cured film. It is composed of a low molecular weight polyisocyanate and an organic solvent which disperses or dissolves these components.

Here, as the colloidal silica, ordinary colloidal silica in which the silanol groups on the surface are not alkyl-substituted or chemically modified, that is, colloidal silica having silanol groups on the surface is used. The polyisocyanate used here is, specifically, an aromatic diisocyanate such as tolylene diisocyanate (TDI), an aliphatic diisocyanate such as hexamethylene diisocyanate (HDI), or a non-volatile form of these to reduce toxicity. It is a polyfunctional (polyvalent) isocyanate compound such as a reduced adduct or isocyanurate, and generally has a low molecular weight of 1,000 or less, which is generally used as a curing agent or a cross-linking agent such as a raw material monomer of a polyurethane resin or an acrylic hydroxyl group-containing resin. It is a molecular polyisocyanate. Therefore, this polyisocyanate generally has a sufficient isocyanate group content of 10% (by weight) or more, and has a sufficiently high reactivity. Although the isocyanate group of the low molecular weight polyisocyanate may be kept free, it is preferable that the isocyanate group is blocked with a blocking agent in terms of storage stability and the like.

That is, a coating composition according to a second aspect is the coating composition according to the first aspect, wherein the low-molecular-weight polyisocyanate is a blocked polyisocyanate whose isocyanate group is blocked by a blocking agent.

As the blocking agent, there can be used caprolactam, methyl ethyl ketoxime, ethyl malonate, etc., which are common as blocking agents of this type.

The coating composition according to claim 3 uses sepiolite, which is a hydrated magnesium silicate clay mineral composed of fine fibrous powder, in place of the colloidal silica. And a low molecular weight polyisocyanate which reacts with and binds to hydroxyl groups on the surface of the sepiolite to form a cured film, and an organic solvent which disperses or dissolves these components.

[0012] The coating composition according to claim 4 comprises:
In claim 3, the low molecular weight polyisocyanate comprises a blocked polyisocyanate whose isocyanate group is blocked by a blocking agent.

Further, these coating compositions include:
As the pigment or the filler, any material can be added as long as it does not react with the polyisocyanate, whereby a coating composition suitable for various specific applications can be obtained.

That is, the coating composition according to claim 5 is the coating composition according to any one of claims 1 to 4,
It further contains zinc powder.

[0015] The coating composition according to claim 6 comprises:
In any one of claims 1 to 4, an aluminum scale is further included.

[0016] The coating composition according to claim 7 comprises:
The semiconductor device according to any one of claims 1 to 4, further comprising a conductive material.

[0017] The coating composition according to claim 8 comprises:
The method according to any one of claims 1 to 4, further comprising a silica balloon.

[0018]

According to the first aspect of the present invention, a cured film is formed by applying the coating composition to a substrate, drying the coating composition, and appropriately heating the coating composition. The formed film has flexibility (flexibility and toughness) unlike a hard but vitreous brittle film formed by applying colloidal silica alone, drying and heating and melting. And also
Unlike a whitened brittle coating (polyurea coating with foaming) formed when a low-molecular-weight polyisocyanate alone is cured by moisture, it is transparent. That is,
According to this coating composition, the silanol groups (hydroxyl groups -OH) on the surface of the colloidal silica and the isocyanate groups (-NCO) of the polyisocyanate react with each other and are bonded by urethane bonds (-NHCOO-), and A composite coating in the form of fine particles cross-linked by polyisocyanate is formed. The reason for the mutual reaction and bonding is that the colloidal silica has a large specific surface area and thus has many silanol groups (hydroxyl groups) on its surface. This is because a component reactive with isocyanate, that is, a compound or substance having active hydrogen is not substantially contained. Therefore, a coating having excellent properties of silica as an inorganic substance and polyisocyanate as an organic substance, that is, high hardness and high flexibility (flexibility and toughness), abrasion resistance (scratch resistance), Heat resistance, adhesion,
A film excellent in antifouling property, chemical stability (acid resistance) and the like can be obtained.

In the second aspect, since the isocyanate group of the low molecular weight polyisocyanate of the first aspect is blocked by the blocking agent, the reaction with the silanol group at normal temperature is prevented, and the one-part coating composition is used. Is formed as According to this coating composition, it is applied, and then heated and baked to a temperature equal to or higher than the dissociation temperature of the blocking agent, so that colloidal silica as an inorganic substance and polyisocyanate as an organic substance as in claim 1. And a combined coating film can be formed.

In the third aspect, sepiolite, which is a hydrated magnesium silicate clay mineral, has many hydroxyl groups (hydroxyl groups and silanol groups coordinated to magnesium) on its surface. Therefore, according to this coating composition, since the component reactive with the polyisocyanate is not substantially contained except for the sepiolite, it is applied to a substrate, dried, and appropriately heated, whereby the composition according to claim 1 is obtained. As in the case of (1), a cured film is formed in a form in which particles of inorganic sepiolite are cross-linked by polyisocyanate as an organic substance. That is, it is possible to form a coating film having excellent properties of an inorganic substance and an organic substance, such as high hardness and flexibility. Sepiolite contains water of crystallization, and water is easily adsorbed. Then, the polyisocyanate reacts with such moisture to generate carbon dioxide gas and form a urea bond with another polyisocyanate. Therefore, in the case of using this sepiolite, the adhesion between sepiolite particles and polyisocyanate is inhibited, and such adhering water or water of crystallization which causes pinholes in the film is sufficiently removed in advance by heating or the like. Preferably.

In the fourth aspect, since the isocyanate group of the low molecular weight polyisocyanate of the third aspect is blocked by a blocking agent, the composition is formed as a one-pack type coating composition. According to the coating composition, the composition is applied, and then heated and baked to a temperature equal to or higher than the dissociation temperature of the blocking agent, whereby, similarly to claim 3, inorganic sepiolite and organic polyisocyanate Can form a composite coating. Also, in this case, since the water of crystallization contained in sepiolite is released at a temperature of about 150 ° C., by using a blocking agent having a dissociation temperature of 160 ° C. or higher,
The reaction between the polyisocyanate and the crystallization water of sepiolite can be prevented.

According to a fifth aspect of the present invention, the coating composition according to any one of the first to fourth aspects further contains zinc powder. Particularly excellent coatings are formed.

According to the sixth aspect, the coating composition according to any one of the first to fourth aspects further includes aluminum scale, so that the coating composition has more flexibility ( (Flexibility, toughness), and a film having more excellent heat resistance is formed.

According to a seventh aspect of the present invention, the coating composition according to any one of the first to fourth aspects further comprises a conductive material. Therefore, a film having excellent radio wave absorption is formed.

[0025] In the eighth aspect of the present invention, the coating composition according to any one of the first to fourth aspects further includes a silica balloon made of a foam and having a high heat insulating property. According to this, a film having more excellent heat insulating properties is formed.

[0026]

First Embodiment First, a first embodiment of the present invention will be described.

In the first embodiment, a polyisocyanate (Trade name: Sumidur L-7, manufactured by Sumitomo Bayer) comprising an adduct of tolylene diisocyanate (TDI) with trimethylolpropane (nonvolatile content: 75% / butyl acetate)
5) and solvent-type colloidal silica (trade name, manufactured by Nissan Chemical Co., Ltd.)
XBA-ST) and a coating composition diluted using xylene as the organic solvent. In addition,
This solvent type colloidal silica (organo silica sol)
Is an aqueous silica sol prepared by repeating the solvent substitution several times of a wet-produced aqueous silica sol, and has a very low water content of 0.11% by weight based on the whole.

Table 1 shows details of the composition and components. In addition,
In the table, the formulations are shown by weight% (the same applies hereinafter).

[0029]

[Table 1]

The coating is prepared by mixing the components of the composition shown in Table 1 at room temperature and then spraying the mixture on the substrate by air spray.
It is formed by drying and curing at room temperature or under appropriate heating. Specifically, after application, the coating is left at room temperature, and after touch drying (about 20 minutes), the coating is heated to 80 ° C. to accelerate the curing.

The characteristics of the formed film are as follows.・ High surface hardness. (Pencil hardness is 6H or more and has flexibility. In addition, the hardness tends to increase with the passage of time.)-Excellent in water resistance.・ Excellent stain resistance (stain resistance).・ Excellent acid resistance, no change even when concentrated sulfuric acid adheres. -Heat resistant temperature 180 ° C (in atmosphere).・ The surface is glossy and transparent. Since this coating composition can form a film having the above characteristics, it can be suitably applied, for example, as a composition for hard coating such as a pre-coated metal.

The reaction mechanism of the coating composition will be considered. As described above, the isocyanate group of the polyisocyanate forms a urethane bond with the silanol group on the surface of the colloidal silica to form a bond, whereby colloidal silica (fine particles of silica) is cross-linked to each other by the polyisocyanate. An inorganic / organic composite coating is formed. Thus, such composite coatings are best cured with polyisocyanate (isocyanate groups) such that they are fully cured (no unreacted polyisocyanate or isocyanate groups remain) and cured with sufficient crosslink density. ) Is formed by blending a slightly excessive amount of colloidal silica (silanol group) with each other and reacting with each other in the substantial absence of other active hydrogen-containing components. The best coatings can be obtained. Since it is difficult to determine the content of the silanol group itself of the colloidal silica, a preferable compounding ratio of the colloidal silica and the polyisocyanate is determined by a test as a ratio at which such a best composite coating is obtained. .
The compounding ratio in the above examples is a compounding range in which good flexibility is obtained together with the maximum coating hardness (pencil hardness of 6H or more).

However, what matters here is water (H ₂ O) which is inevitably mixed into the composition, and particularly water which adheres to the surface of the colloidal silica in a small amount. That is, colloidal silica is negatively charged in an organic solvent and is stabilized by repulsion between particles.However, when the organic solvent volatilizes after application of the composition, the charge balance is lost, and the colloidal silica particles aggregate with each other. And aggregate. Then, when the colloidal silica aggregates as described above, the specific surface area decreases, while water adhering to each particle is collected on the surface of the aggregated coarse particles. That is, such a small amount of water, which has a low volatilization rate, temporarily increases relatively to silanol groups when the organic solvent volatilizes and the colloidal silica aggregates. In addition, such a water content increases rapidly as the volatilization speed of the organic solvent is higher and, therefore, the aggregation speed of the colloidal silica is higher.

Such water, which is an active hydrogen-containing compound, reacts with polyisocyanate in competition with silanol groups of colloidal silica to produce carbon dioxide (CO ₂ ).
And a urea conjugate (buret) is generated. In other words, water not only inhibits good cross-linking between polyisocyanate and colloidal silica, but also causes a large amount of water and, if the reaction is relatively rapid, causes foaming of the film or generation of pinholes.

However, such water will eventually evaporate and volatilize even if it takes some time. Therefore, if a polyisocyanate having low reactivity at room temperature is used, there is not much problem. It does not become. However, an aromatic polyisocyanate having high reactivity and curable even at room temperature, like the TDI adduct in the above example,
The rate of reacting with water in competition with silanol groups is also high. Therefore, when the volatilization rate of the organic solvent is high and the agglomeration rate of the colloidal silica is high, the organic solvent reacts abruptly with H ₂ O which is relatively increased by the aggregation.

Therefore, when an aromatic polyisocyanate having a high reactivity is used as the polyisocyanate, the polyisocyanate and the silanol group of the colloidal silica must be formed before the aggregation of the colloidal silica due to the volatilization of the organic solvent. It is preferred that the reaction with has progressed to some extent. That is, the volatilization rate of the organic solvent is preferably relatively slow so that the aggregation rate of colloidal silica is relatively low. Thereby, it is possible to suppress a rapid reaction of the colloidal silica with water at the time of aggregation, and to prevent foaming of the coating or generation of pinholes even when the amount of water is relatively large. However, conversely, if the volatilization rate of the organic solvent is too slow, not only the touch drying time of the coating film becomes long, but also the curing reaction proceeds too much before the organic solvent volatilizes, causing the coating film to gel. Will be. Therefore, it is necessary that the organic solvent has a certain volatilization rate.

As described above, the volatilization rate of the organic solvent is important for forming a more excellent cured film, and it is preferable to control the rate. The evaporation rate of the solvent is controlled by changing the solvent in accordance with the ambient temperature or the like, by combining a plurality of solvents having different boiling points, or by adjusting the mixing amount (diluting amount) with the coating viscosity. It can be carried out as appropriate by changing it while changing it. Specifically, in the first embodiment described above, xylene having a slightly lower volatilization rate than the medium is used among the organic solvents, and the coagulation rate of the silica particles, that is, the volatilization rate of the solvent is adjusted slightly lower. However, the coating formed thereby contains a reaction product (urea bond) of the polyisocyanate and water or the like adhering to the silica particles, and the polyisocyanate is not purely reacted with only colloidal silica. However, since the water content is sufficiently small due to the use of the solvent type colloidal silica, the film is transparent and almost complete in surface hardness and the like as in the above-mentioned film characteristics.

By the way, an aromatic polyisocyanate having a high reaction rate (“Sumidur L-75”),
The coating composition of this first example using an adduct of tolylene diisocyanate produces a gel when left for a long period of time, so it is suitable to prepare it immediately before use. This composition has a high curing speed, and can be dried at room temperature (room temperature curing) without heat treatment. Therefore, it can be formed as a room temperature drying type two-component coating composition.

The highest reaction rate among aromatic polyisocyanates is 4,4'-diphenylmethane diisocyanate (MDI) or a derivative thereof (about three times that of TDI). However, this MDI has an extremely high reactivity selectively to moisture as a monomer material of a moisture-curable polyurethane prepolymer. Therefore, when this MDI is used, it is preferable to block the isocyanate group with a blocking agent so as not to react with water adhering to silica particles and the like as in the examples described later.

As the polyisocyanate, an aliphatic polyisocyanate having generally low reactivity, for example, "Sumidur N-3500" (trade name of Sumitomo Bayer) comprising an isocyanurate of hexamethylene diisocyanate (HDI) is used. You can also. In this case, the reaction rate at room temperature is sufficiently low, so that the composition can be stored for a long time (about one year). However, a heat treatment for accelerating the reaction is required for forming the coating film. In the case of this composition which is dried and cured by heating, moisture is volatilized by the heat treatment, so that the above-mentioned adjustment of the volatilization rate of the organic solvent is not so important.

The coating composition of the first embodiment corresponds to the first aspect of the present invention.

Second Embodiment Next, a second embodiment of the present invention will be described.

In the second embodiment, a block type polyisocyanate, that is, a block isocyanate obtained by blocking an isocyanurate of hexamethylene diisocyanate (HDI) with caprolactam (trade name: Desmodur BL-3175, manufactured by Sumitomo Chemical; % /
Solvent naphtha 100) and a coating composition combining sepiolite (trade name: Adeplus, manufactured by Takeda Pharmaceutical Co., Ltd.).

Table 2 shows details of the composition and components.

[0045]

[Table 2]

The coating composition of this example was prepared by mixing the components of the composition shown in Table 2 at room temperature, and the coating was applied to a substrate by air spraying or brushing. After heating at 30 ° C for 30 minutes,
It is formed by heating and drying at 160 ° C. for 40 minutes.

The characteristics of the formed film are as follows.・ Thick film coating is possible.・ Excellent strength (no cracking or peeling even at 1000 μm or more; excellent in impact and bendability).・ Moisture is adsorbed on the surface. -Heat resistant temperature 160 ° C (in atmosphere). Due to the above properties, this coating composition can be suitably applied, for example, for thick film high strength hard coating.

Next, the reaction mechanism of the coating composition using sepiolite will be described.

Sepiolite is a fine fibrous hydrated magnesium silicate clay mineral commonly called mountain leather (mountain skin), mountain cork, or mountain wood, and is a three-dimensional chain formed by alternately stacking bricks. It has a crystalline structure, and tunnel-like pores are formed in the chain-like gap along the length direction of the fiber. Therefore, the surface area is as large as 300 m ² / g, and the surface contains a large amount of hydroxyl groups (—OH) and silanol groups (—SiOH) coordinated with highly reactive magnesium. Further, the crystal water is contained in the tunnel-shaped pores as the binding water, and the crystal structure is maintained. The water of crystallization is released at a temperature of about 150 ° C.

Therefore, since sepiolite contains water of crystallization together with hydroxyl groups, when used in combination with polyisocyanate as it is, the water of crystallization is contained in the pores as bound water, but has lower reactivity than mere attached water.
Reacts with polyisocyanates in competition with hydroxyl groups and produces CO ₂
And a urea conjugate (buret) is formed. Therefore, when the reaction is rapidly performed, CO ₂ is also rapidly generated, and a film formed thereby has many pinholes.

Therefore, in a system using this sepiolite, it is preferable that the water of crystallization be released from the sepiolite in advance before the polyisocyanate reacts with the hydroxyl group on the surface of the particles of the sepiolite and bonds by a urethane bond. Therefore, in the second embodiment, a blocked polyisocyanate whose isocyanate group is blocked with a blocking agent is used as the polyisocyanate, and the dissociation temperature of the blocking agent is higher than the temperature at which water of crystallization is released. You are using

That is, after the application of the composition, the crystallization water and other water in the sepiolite ("Aid Plus") are released by heating sufficiently at a temperature of 150 ° C., and then heated to 160 ° C. As a result, caprolactam, which is a blocking agent, is dissociated, and the free isocyanate group of the HDI isocyanurate reacts with the hydroxyl group on the surface of the sepiolite particles to be mutually bonded by urethane bonds. And the film formed by this,
As in the case of using colloidal silica, it contains a certain amount of a reaction product of the polyisocyanate and water (urea-bound compound). However, while incorporating the urea conjugate, most of the time the polyisocyanate reacts to crosslink the sepiolite particles, forming a coating with the above described excellent properties.

The coating composition of the second embodiment comprises:
In particular, it corresponds to the aspect of claim 4. In this composition using sepiolite, an unblocked polyisocyanate can be used as the polyisocyanate as in the first embodiment. The coating composition corresponds to the third aspect of the present invention. However, in this case, when a highly reactive polyisocyanate is used, a film having many pinholes is formed by a rapid reaction with water of crystallization as described above. Those with a slow reaction rate are suitable. In this case, it is more preferable that the water adhering to the sepiolite and the water of crystallization thereof are removed by heating it at about 150 ° C. in advance.

Third Embodiment Further, a third embodiment of the present invention will be described.

In the third embodiment, the block type aliphatic polyisocyanate (trade name: Desmodur BL-3175 manufactured by Sumitomo Bayer) used in the second embodiment and the solvent type colloidal silica used in the first embodiment ( This shows a coating composition in combination with Nissan Chemical's trade name: XBA-ST).

Table 3 shows details of the composition and components.

[0057]

[Table 3]

The coating was prepared by mixing the components having the composition shown in Table 3 at room temperature, and then spraying the mixture on the substrate with an air spray.
It is formed by heating and curing at 60 ° C. for 40 minutes.

The film characteristics are almost the same as those of the first embodiment.
Therefore, for example, it can be applied as a hard coating or the like. However, this polyisocyanate (block of HDI isocyanurate) is a block type in which the reaction between the silica particles and the polyisocyanate does not occur until a temperature of 160 ° C. at which the blocking agent (caprolactam) dissociates, and adheres to the silica particles. Since water and the like are removed out of the system, a film having a higher reaction density between the silica particles and the polyisocyanate can be easily formed. Adjustment of the volatilization rate of the organic solvent corresponding to the reaction rate of the polyisocyanate is not important here, and an appropriate organic solvent may be selected and used so as to be most suitable for the coating conditions or the film forming conditions after the coating. it can.

The coating composition of the third embodiment is:
In particular, it can be said that it corresponds to the aspect of claim 2 and also to the aspect of claim 1.

<Fourth Embodiment> In a fourth embodiment, a pigment or a zinc powder as a filler is further added to a film-forming component composed of a combination of a polyisocyanate and colloidal silica.

Table 4 shows the details of the composition and components. That is,
The specific components of the polyisocyanate and colloidal silica are the same as in the first embodiment.

[0063]

[Table 4]

The coating on the substrate can be performed by air spraying or brush coating. The composition is dried and cured by leaving it at room temperature for 20 minutes (touch drying) and then leaving it at room temperature for 24 hours (complete drying). ) Or, for example, 80
The heat treatment can be performed in combination with a heat treatment at 20 ° C. × 20 minutes.

The coating characteristics are as follows.・ Excellent corrosion protection.・ Excellent drying properties. -The heat resistance temperature is 150 ° C (in the atmosphere). This coating can be suitably applied, for example, as a composition for rust-proof coating on various metal base materials due to the above-mentioned physical properties. The fourth embodiment particularly corresponds to the fifth aspect.

Fifth Embodiment In a fifth embodiment, a combination of a polyisocyanate and colloidal silica is further added with a leafing aluminum paste as a heat-resistant pigment.

Table 5 shows the composition and physical properties of the components. In addition,
"Sumidur N-3500" (trade name of Sumitomo Bayer) consists of an isocyanurate form of hexamethylene diisocyanate (nonvolatile content 100%).

[0068]

[Table 5]

The composition can be applied to the substrate by air spraying or brushing, and the applied composition can be dried and cured by leaving it at room temperature for 24 hours (touch drying) and then leaving it at room temperature for 7 days (completely Drying) or by heating at 160 ° C. for 40 minutes.

The coating properties are in particular as follows: -Heat resistant temperature 180 ° C (in atmosphere). This coating can be suitably applied, for example, as a heat-resistant coating composition due to the above characteristics. The fifth embodiment particularly corresponds to the sixth aspect.

Sixth Embodiment In a sixth embodiment, a conductive material is further mixed with a film-forming component composed of polyisocyanate and colloidal silica. As this conductive material, graphite having elasticity (a joint research product name: Elephite with Kowa Sekiyu, Mitsui Mining, Kyushu Technical Laboratory, Industrial Technology Institute) was used.

Table 6 shows the details of the composition and components.

[0073]

[Table 6]

The coating on the substrate can be performed by air spray. The applied composition can be dried and cured by leaving it at room temperature for 24 hours (touch drying) and at room temperature for 7 days, as in the fifth embodiment. (Complete drying) or by heating at 160 ° C. for 40 minutes.

The formed coating has the following characteristics in particular. -Heat resistant temperature 180 ° C (in atmosphere). -It has conductivity. By having this property, this coating film can be suitably applied, for example, as a conductive coating composition for absorbing radio waves. The sixth embodiment particularly corresponds to the seventh aspect.

<Seventh Embodiment> In a seventh embodiment, a film-forming component composed of a combination of a polyisocyanate and sepiolite is further added with a phyllite composed of a silica balloon which is an insulating filler. More specifically, the silica balloon is further added to the coating composition component of the second embodiment.

Table 7 shows the details of the composition and components.

[0078]

[Table 7]

The application to the substrate can be performed by air spray or brush coating. The applied composition can be dried and cured by heating at 150 ° C. for 30 minutes,
It can be carried out by heating at 60 ° C. for 40 minutes.

The films formed are as follows.・ Excellent heat insulation (in atmosphere). This coating is particularly suitable for insulating heat of 100 ° C. or more, and is suitable as a composition for heat-insulating coatings for building panels and the like. The seventh embodiment particularly corresponds to the eighth aspect.

In each of the above embodiments, the materials shown in the tables are used. However, the present invention is not limited to the above. Also, it does not prevent the addition of additives as appropriate.

[0082]

As described above, the coating composition according to the first aspect of the present invention forms colloidal silica having a silanol group on the surface and a silanol group on the surface of the colloidal silica by reacting and bonding with each other to form a cured film. , And an organic solvent which disperses or dissolves these components.

Therefore, according to this coating composition, colloidal silica having a large specific surface area and having many silanol groups on its surface is used. In addition to this colloidal silica, a component reactive with polyisocyanate is used. Since the composition is substantially not contained, the composition is applied to a substrate and dried to form a cured film in which the colloidal silica and the polyisocyanate react with each other and bond. Therefore, a coating having both the characteristics of silica as an inorganic substance and the characteristics of polyisocyanate as an organic substance, that is, high hardness and flexibility (flexibility,
Toughness), abrasion resistance (scratch resistance), heat resistance,
There is an effect that a film excellent in adhesion, antifouling property, chemical stability and the like can be obtained.

The coating composition according to claim 2 comprises:
In claim 1, the polyisocyanate comprises a blocked polyisocyanate whose isocyanate group is blocked by a blocking agent.

Therefore, according to this coating composition, a low molecular weight polyisocyanate which is blocked with a blocking agent is used, so that the composition can be formed as a one-part liquid form. This has the effect that long-term storage stability can be ensured. Also,
According to this coating composition, since the formation of the cured film is performed by heating and baking the composition at a temperature equal to or higher than the dissociation temperature of the blocking agent, it is possible to remove water adhering to the colloidal silica in advance. There is also.

The coating composition according to claim 3 comprises:
It is characterized by comprising sepiolite, a low molecular weight polyisocyanate which reacts with and binds to hydroxyl groups on the surface of the sepiolite to form a cured film, and an organic solvent which disperses or dissolves these components.

Therefore, according to this coating composition, sepiolite having a large specific surface area and having a large number of hydroxyl groups on the surface is used. In addition to the sepiolite, a component reactive with polyisocyanate is substantially contained. Since this composition is not applied, the composition is applied to a substrate and dried to form a cured coating in which sepiolite, which is an inorganic substance, and polyisocyanate, which is an organic substance, are combined with each other as in the case of claim 1. Can be. That is, there is an effect that a coating having excellent characteristics such as high hardness and high flexibility (flexibility and toughness) can be obtained by combining the characteristics of the organic material with the characteristics of the inorganic material.

The coating composition according to claim 4 comprises:
In claim 3, the polyisocyanate comprises a blocked polyisocyanate whose isocyanate group is blocked with a blocking agent.

Therefore, according to this coating composition, since the blocked polyisocyanate is used as the polyisocyanate, the composition can be formed as a one-part liquid form. There is an effect that the property can be secured. Further, according to this coating composition, since the formation of a cured film is performed by heating and baking the composition to a temperature equal to or higher than the dissociation temperature of the blocking agent, water such as water of crystallization contained in sepiolite is converted to its hydroxyl group. There is also an effect that it can be removed in advance before reacting with the dissociated polyisocyanate.

The coating composition according to claim 5 comprises:
In any one of claims 1 to 4, the composition further comprises zinc powder as an essential component.

Therefore, according to this coating composition, since zinc powder is further contained, in addition to the effects of claims 1 to 4, an effect of obtaining a film having particularly high rust prevention properties can be obtained. There is.

The coating composition according to claim 6 is:
In any one of claims 1 to 4, an aluminum scale is further included as an essential component.

Therefore, according to this coating composition, aluminum scales which are heat-resistant pigments are further included, so that a coating having higher heat resistance can be obtained in addition to the effects of claims 1 to 4. There is an effect that can be.

The coating composition according to claim 7 comprises:
In any one of claims 1 to 4, a conductive material is further included as an essential component.

Therefore, according to this coating composition, since a conductive material is further contained, in addition to the effects of the first to fourth aspects, it is possible to obtain a film having conductivity in combination. There is.

The coating composition according to claim 8 is:
In any one of claims 1 to 4, a silica balloon is further included as an essential component.

Therefore, according to this coating composition, since a silica balloon which is a heat insulating filler is further included, a coating film having high heat insulating properties is obtained in addition to the effects of claims 1 to 4. There is an effect that can be.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-146954 (JP, A) JP-A-59-120650 (JP, A) JP-A-59-33358 (JP, A) 58498 (JP, A) JP-A-50-98959 (JP, A) JP-A-51-47046 (JP, A) JP-A-50-19885 (JP, A) JP-A-51-119095 (JP, A) JP-A-60-120750 (JP, A) JP-A-2-167365 (JP, A) JP-A-61-266 (JP, A) JP-A-58-204055 (JP, A) JP-A-58-204056 (JP, A) JP-A-64-11154 (JP, A) JP-A-64-14269 (JP, A)

Claims (8)

(57) [Claims] 1. A colloid having a silanol group on its surface.
Silica and silanol groups on the surface of the colloidal silica
Low molecular weight polyisocyanates that respond and combine to form a cured coating
Over preparative and coating composition characterized by comprising the organic solvent the components dispersed or dissolved. 2. The low molecular weight polyisocyanate according to claim 1 ,
Isocyanate groups blocked with a blocking agent
Claims characterized in that it comprises cupric isocyanate
2. The coating composition according to 1. 3. A reaction between a sepiolite and a hydroxyl group on the surface of the sepiolite to form a bond.
A coating composition comprising: a low-molecular-weight polyisocyanate that forms a cured film by heating; and an organic solvent that disperses or dissolves these components . 4. The polyisocyanate according to claim 1, wherein
Block poly in which cyanate groups are blocked with a blocking agent
4. The method according to claim 3, comprising an isocyanate.
Coating composition described above. 5. The process according to claim 1 , further comprising zinc powder.
The coating according to any one of claims 1 to 4.
Composition. 6. The method according to claim 6 , further comprising aluminum scale.
The co-processor according to any one of claims 1 to 4,
Coating composition. 7. The method according to claim 7 , further comprising a conductive material.
The coating according to any one of claims 1 to 4.
Composition. 8. The method according to claim 1 , further comprising a silica balloon.
The code according to any one of claims 1 to 4,
Ting composition.